A man has been arrested after police uncovered his sex business in Ho Chi Minh City. His choice method of advertising? Business cards.

Nguyen Ba Huy, 43, was apprehended after police discovered two of his sex workers with their clients in a local hotel together. Police arrested him for running a sex business in the backpackers area in District 1, Thanh Nien News reports.

Prostitution is illegal in Vietnam, and operators of sex businesses, like Huy, can go to jail for running them.

Huy made a habit of leaving his business cards in bars and restaurants. Though most physical, printed business cards (88%) are thrown out within one week, they are still a well-established and relied upon tool in social and business networking.

His business card was simple, and had a minimalist design. It featured only his first name, his phone number, and the word “Girls.” Huy recruited girls around the age of 20, and charged $100 USD for each visit.

Thanh Nien News reported last September that although Ho Chi Minh City made prostitution illegal about 10 years ago, the sex business is still thriving. A report submitted to the city last year says that the sex industry has become more complicated and that foreign tourists are targeted more often.

The “backpackers area” where Huy ran his business is called such because it’s a common area for tourists to visit, which was Huy’s target market for his services.

By the end of 2014, authorities had found almost 60 streets and public places where prostitution was offered in the city, and hundreds of shops that likely offer the service as well.